Why your brain flips over visual illusions

Video: Brain-flip illusion

By Jessica Griggs

Say what you see

(Image: Mary Evans Picture Library)

IT’S a big skull. No, wait, it’s two people under an arch. Hold on, it’s a skull again. Two very different images can be perceived in the trick picture Blossom and Decay (see right). Now we are one step closer to working out how the brain spontaneously flips between such views, with the discovery of what may be the relevant brain region.

The precise neural mechanism that provokes the brain to switch its view of a scene is unknown, but it is thought to play a major role in perception by acting as a sort of reality check, says Ryota Kanai of University College London. “We need a trigger to prompt possible different interpretations so that we don’t get stuck with a potentially incorrect interpretation of the world.”

To find out which part of the brain might

To continue reading this premium article, subscribe for unlimited access.